Okay, a few points,
One: this is a bit of a nitpick but
bobucles wrote:The best solar solution is going to affect the net value of panels as little as possible, while achieving the maximum output in how players have to rethink their gameplay. I don't think that's an unfair statement to make.
The first half of this isn't really important, except as a thing that emerges from a dozen other factors. The value of solar panels can be changed a lot so long as,
1: The effort the developers put in is worth the engagement of the players out.
2: The value of solar panels as a solution is weighted against the engagement player has setting up solar panels, vs setting up any other power system.
So in short, I would say that the value of solar panels should be balanced against the difficulty of the puzzle they provide. ("Interestingness of the problem" in my previous words)
Two: This bit?
bobucles wrote: That's what we like to call a "puzzle", and one with a rather modest difficulty.
condescending. For these forums at least. Seriously, if we didn't not only know what a puzzle is, but also decide for ourselves that Solar as it stands is a boring puzzle, we wouldn't be complaining about it the way that we are
And lastly, but certainly not least, because you skipped my bit, I'll note that while I opened up solar-thermal as way to make a resource cost work without repair packs (by having a very small oil cost at the highest efficiencies instead), in actuality it falls under a very different category:
4) Increase the system complexity of solar.
Fairly simple: a more complex system give the player more principles to work with, more pieces to the puzzle as it were, and they think harder to set things up. Once things are set up however, everything is fairly simple to copy into a blueprint and paste.
So, allow me to go into this in a bit more depth:
roadwaysthermal. Step one:
The reason I proposed Solar Thermal, and the beautiful thing about it, is that its complexity scales with its efficiency
: You can very easily have an offshore pump at one end, run pipe through a few dozen panels, run a steam engine off the heat, and call it a day. You'll run into problems with losing working time of course as the fluid needs to evaporate each morning, but the imaginative player has many ways to counter that, from simply adding backup boilers to, accumulators as we know them, to storing hot water produced by day, for use by night
, though that last one will likely require turning off the flow at the right time. Something much easier with coal power.
Solar-thermal: Step two:
But of course, this is only the beginning. With heat exchangers and heating oil the system is more complicated to set up, but once it works, it works perfectly. (or with minor heating oil loss over time, whichever works)
The oil and water pass through the heat exchangers through separate pipes separate lines and both fluids are allowed to flow freely, basically as a 3x1 or 3x3 boiler that uses no fuel, and as they remain in the same heat exchanger their temperatures slowly equalize. With this, two fluid cycles exist instead of one: one for oil gaining heat in solar panels, losing it in heat exchanges, and returning the the panels and the offshore pump --> heat source --> steam engine chain we all know and love.
The core idea with heating oil and heat exchangers however, is that in order to heat up a given amount of water, you only need a fraction as much oil, meaning that the oil travels slower. If your fluid is traveling a third as fast, it's spending three times as long solar panel, and thus each panel is three times as efficient.*
Now there are two ways to do this: Either the oil can get much hotter much easier, or it can have a higher specific heat than water. (read: the recipe for the heat exchanger only drops it one degree for every three degrees it heats up the water) I favor water having the higher specific heat and oil having the higher temperature, because means that a countercurrent exchange, while it is naturally more efficient, is not strictly necessary, instead being a neat trick players reward themselves for finding. Which is a theme here: This entire setup with solar-thermal is the game finding a dozen ways to say "Hey, you don't have to do this, and it is a bigger problem/harder puzzle/small extra thing to consider... but it's better." and teaching players to chase that voice.
The fact that oil getting hotter but having a lower specific heat is more realistic... is just icing on the cake really. That said, this specific heat stuff isn't actually necessary and if it's not worth changing the code, there are workarounds.
In any event, you've set up your solar plant with heat exchangers and heating oil and now you're doing great: You've got a setup where you've got a bunch of of solar panels setup to run, three times as efficient as before.
Solar-thermal: Step three:
Finally, and this is the insidious part, eventually you're going to hit a peak: Pumping capacity
With inline pumps, fluid can only travel so fast and so far. About 750 tiles for a single pump working at 30 units/second but that length decreases massively as you add more speed.
Now I haven't actually tested this, but from everything I know it makes sense that out in the reaches, you can just send oil through your pipes in parallel. Up back at the base and for longer steam engine lines, where your mixing all those fluid lines together at the central power hub, you need to pump differently. And thus the player is encouraged to learn the mechanics of high speed pumping.
In the end, the greater the throughput of the heating oil, the bigger the solar farm can be, and the more engines it can power. And once you hit a peak, or are happy with what you want, you just copy the pieces of the setup into your blueprints, and paste it down again when you need it anew.
All of this is based on a few very simple and knowable principles:
1: Solar panels and heat exchangers, like boilers, don't pump fluid but merely heat up or equalize the temperature of the fluid(s) as it remains within the object and the object has a source of energy.
2: Steam engines burn through a set amount of water per second to produce power. More steam engines need more hot water.
3: Fluids in Factorio have a speed limit, based on distance, which can be overcome via adding more pumps, more frequently.
So you go from step one! "Hey! Free boilers by daylight!" To step two: "Oil and heat exhangers triple the efficiency!" To step three: "Pumping mechanics help make my system bigger!"
So this is why I proposed solar-thermal: it's three new items, a solar boiler, a fluid that gets hotter than usual (and it can even just be light oil, heavy oil, or petroleum gas with some code changed), and a boiler that equalizes the temperatures of different fluids with a bias based on specific heat, but it gets this
complex. And each machine is pretty simple and behaves with very consistent principles.
And it's still only ever as complex as you let it get. It's a patient puzzle that challenges the player in their own time.
*Why specifically three times as efficient? Three reasons: First and most importantly it's a big number that rewards the most complicated part of the setup process. Secondly, using oil as a working fluid needs to be at least twice as efficient as using water as a working fluid, in order to match the flow rate of offshore pumps to the flow rate of small pumps and make the third stage meaningful. Finally, in the real world water has a specific heat of ~4 and boils at 100 degrees Celsius. Oils have a specific heat of ~2 (a little more for petroleum based oils, a little less for vegetable oils) and the peak temperature of steam engine based solar thermal energy is around 600 degrees Celsius. So realism as a tool to inform gameplay.
The greatest gulf that we must leap is the gulf between each other's assumptions and conceptions. To argue fairly, we must reach consensus on the meanings and values of basic principles. -Thereisnosaurus